The invention generally relates to an improved arrangement to provide a variable geometry flameholder in a turbine engine. More particularly, an inventive flameholder provides a streamlined geometry when a turbine engine augmentor is not operating and a “turbulent” geometry when the augmentor is operating.
Turbine engines may have afterburners, or augmentors, located at the rear of the engine upstream of an exhaust nozzle. Augmentors utilize unused oxygen from the turbine engine to obtain a second combustion. The second combustion provides additional thrust from the turbine engine. An augmentor includes flameholders to create low velocity wakes to stabilize combustion in the high velocity turbine engine exhaust.
Flameholders have the disadvantage of creating pressure loss in the airflow of the turbine engine even when the augmentor is not operating. The pressure loss when the augmentor is not operating decreases the thrust of the turbine engine.
Prior turbine engine augmentors have attempted to utilize flameholders of varying geometry such that the flameholder is arranged to provide a more streamlined airflow when the augmentor is not operating. In one known turbine engine, the spraybars and flameholders were arranged in concentric rings about the inner case of the turbine engine. Actuators for moving the flameholders were located within the inner case in order to reach the flameholders. However, due to the excessive heat within the turbine engine the components required for varying the flameholder position have had limited lifespan. Therefore, variable geometry flameholders have provided limited use in application.
An arrangement to provide a variable geometry flameholder which has increased durability is needed.